This invention relates to polyurethanes and to a process for their preparation.
Polyurethanes constitute a broad class of polymeric materials having a wide range of physical characteristics. The polymers are produced by the reaction of a polyisocyanate with a polyfunctional compound having an active hydrogen in its structure. This active hydrogen compound is generally a liquid or solid capable of being melted at relatively low temperatures. Most commonly, the active hydrogen compound contains hydroxyl groups as the moieties having the active hydroxyl groups and thus are termed polyols, e.g., the polyols of polyesters, polyester amides, or polyethers, or mixtures of two or more such materials. For reasons of commercial availability and cost, the polyols most commonly employed in the preparation of polyurethanes are the polyethers having hydroxyl terminated chains and hydroxyl terminated polyesters.
Polyurethanes have found extensive commercial application because of their excellent physical properties. These thermoplastic polymers are suitable for molding, spraying and coating products where tensile strength, thermostability, and impact resistance are required.
In view of the fact that a majority of the active hydrogen-containing organic compounds are prepared from nonrenewable resources, it would be highly desirable to prepare polyurethanes from active hydrogen-containing compounds which are obtained from renewable resources.